how to resolve P0420 code in Tesla Model 3 Highland (2024-present)

Solution

1. Preparation

• Gather necessary tools and parts.
• Disconnect the negative terminal of the battery to prevent electrical shorts.
• Allow the vehicle to cool down if the engine has been running.

2. Inspect and Replace Oxygen Sensors

1. Locate the upstream and downstream oxygen sensors.
2. Use a socket wrench to carefully remove the sensors.
   • Tools Required: O2 sensor socket, ratchet, and extension.
3. Inspect the threads and wiring of the removed sensors for damage.
4. Install new oxygen sensors by threading them into place and tightening to manufacturer specifications (typically around 30 ft-lbs).
5. Reconnect the electrical connectors securely.

3. Inspect and Replace Catalytic Converter (if necessary)

1. Check the catalytic converter for signs of physical damage or blockage.
2. If replacement is needed, disconnect the exhaust pipes from the catalytic converter.
   • Tools Required: Socket set, exhaust pipe cutter (if needed).
3. Remove the old catalytic converter and install the new one.
   • Ensure proper alignment and secure all bolts/nuts to recommended torque settings (usually around 25-35 ft-lbs).
4. Reconnect any exhaust components removed during the process.

4. Clear Codes and Test

1. Reconnect the negative battery terminal.
2. Use an OBD-II scanner to clear the P0420 code and any other related codes.
3. Start the vehicle and allow it to reach operating temperature.
4. Conduct a test drive to ensure the check engine light does not reappear.